Spark plug



H. A. VILA SPARK PLUG Nov. 1, 1938.

Filed Sept. 25, 1957 Patented Nov. 1, 1938 UNITED STATES PATENT OFFICE 1 srAaK PL G Heriberto A. Vila, New York, N. '1. Application September 25, 1937, Serial No. 165,679

1': Claims. (01. 123169) The present invention relates to improvements in spark plugs for high compression high speed engines of the gas type, and has for its principal objects the providing of a gapless spark plug, a

closed slotless compact shell for the prevention of gas and oil leakages from the engine cylinder to the interior of the plug. Besides, and as the special feature in the present invention, a replaceable or restorable plug-in gapless compact spark-gap is provided. The present invention with its relative features just mentioned will provide a plug which will not collect oil, carbon or ashes and will be almost absolutely leakless as such a plug has no cavities or slots in the shell nor an empty gap between the grounded electrode and the insulated electrode.

The shell used in the present invention is completely closed to leakages from the interior of the engine and for that purpose a gapless compact '20 spark-gap is provided in the. bottom of said shell.

This gapless spark-gap or sparker, as it is called in my present invention, is a composite compact circuit formed of two adjacent metallic portions serving as opposite electrodes and a solid dielec- 25 tric or insulation filling and compressed or molded in thespace separating them. The solid dielectric takes the place of the gas dielectric commonly used in ordinary plugs of the empty gap and serves besides as a holder or binder for the two opposite electrodes.

The providing of a replaceable spark-gap or sparker will discontinue and substitute the usual procedure of cleaning reconditioning and setting the gaps of used or worn out plugs. Once a 35 sparker is used for a certain number of hours of continuous sparking it is thrown away and replaced for a brand new one. This sparker is nec- I essarily and sufliciently made of small proportions and of low cost manufacture. This sparker 40 should be manufactured in the same way that the electric light bulbs and radio tubes are made, in other words, for the purpose of being used up in all its capacity, not to be repaired but replaced,

45 as its cost of production should be less than its cost of reconditioning.

Other objects will becomeapparent as the description goes on and by examination of the appended drawing, wherein,

50 Fig. 1 is a preferred form of a spark plug in longitudinal section embodying all-the features claimed by my, present invention.

Fig. -2 is a longitudinal section of the sparker or gapless spark-gap of my invention showing'a pre- 55 ferred construction of the same.

Fig. 3 is a side elevation view of the sparker illustratedby the section of Fig. 2.

V Fig. 4 is the top view of the sparker shown in Figs. 2 and 3.

Fig. 5 is the bottom view of the same sparker. 5

Fig. 6 is a side elevation view of a spark plug partly in section and showing the particular 'construction suitable for insertion of the corresponding plug-in spark-gap shown in Fig. 3.

'Figs. 7 and 8 are, respectively, the elevation 10 and bottom view of .the tool used in connection with the sparker shown in Figs. 2 and 3.

Referring to Fig.1 there is the conventional insulated central spindle I terminated in its lower end with the head 2, and at the top with the binding post 3. The spindle I is surrounded from the .binding post 3 to the head 2 by the insulator 4.

The solid composite formed by the spindle I and the insulator l is embraced and supported by the conventional bushing 5 as in Fig. 6, or the shell 6 of Fig. 1, which are electrically insulated from the spindle I by an inner extension of the proper insulation 4. This last bushing 5 is exteriorly screw threaded to permit of being screwed into a larger bushing or shell Ii. And this last shell 6 is likewise exteriorly screw threaded to permit of being screwed into a corresponding socket in the engine casting. The shell 6 at the same time carries at its lower end the grounded electrode I which nears the insulated electrode 9 by a gap 8. This gap ordinarily is filled with a gas dielectric, but in the present invention the dielectric is a solid one.

In Figures 2, 3, 4 and 5 are illustrated the different views of the 'replaceable gapless sparkgap of my invention, and in said figures, I0 is a short spindle made of a heat conductive metal, surrounded by an insulating sleeve preferably of rolledmica which is indicated by :3; immediately surrounding said sleeve I3 there is an ex- 40 teriorly screw threaded or attachable bushing of heat conductive metal, this bushing tightly pressing said insulating sleeve I3 and is indicated in the figures by II; at the same time this bushing II screws or attaches into the lower opening of '45 the shell 6 in Fig. 1 and closes this shell by its bottom providing a gas tight sealing. Immediately on top of the bushing II there is an annular portion of insulation I2 preferably of Bakelite or other good molded insulation; this annular insulation presses against and around the sleeve I3; and the top of the spindle Ill is outwardly bent over a. metallic washer I4 which in turn is resting on top of the insulating ring I2. The short spindle III has in its lower end an extension in the form of a disc with an outward circular border 8 acting as the insulating electrode for the spark gap. The metallic bushing i I has a downward converging border I nearing the border 9 of the short spindle; that border 1 acts as the grounded electrode for the spark gap. Between the electrodes 1 and 9 there is a portion dielectric solid material compressed between said electrodes, the dielectric 8 made preferably of mica washers.

As said before the sparker illustrated in Figs. 2 and 3 is screwed or attached under the shell 6 and in its lower entrance for the purpose of closing and sealing said shell. At the same time when said sparker is tightly screwed or attached in the shell 6 the top of the short spindle makes tight contact with the downwardly pointed head 2 of the spindle l of the core of the spark plug in Fig. 1. Beneath the surface of the bushing ll there are two oppositely disposed holes or recesses for the purpose of applying the tool illustrated in Figs. 10 and 11 which tool serves to tighten the sparker into the shell 6.

The replaceable spark-gap or sparker shown in Figures 1, 2, 3, 4 and 5 is a compact composite bushing composed of two adjacent metallic portions or members l and H and a compressed solid dielectric 8, l3 and I 2 between said metallic members, the dielectric at 8 having an exterior free surface over which slides or jumps the spark provided by the spark-gap. The metallic portion or member H making direct tight contact with the shell 6 thus forming the grounded electrode at I for said sparker; the other metallic member ID being in contact with the spindle l of the spark plug of Fig. 1 thus forming the insulated electrode at- 9 for said sparker, the spark discharge provided by said sparker jumping and sliding over the outside free surface of the solid dielectric at 8, the small outside free surface of said solid dielectric facing the outside of the spark plug.

The compressed solid dielectric formed by the insulations 8, l2 and I3 can be made of'a moldabledielectric material as Bakelite, glass or porcelain. In the preferred form shown in Fig. 2, 8 are compressed mica washers, i3 is a sleeve of rolled mica, I2 is a molded piece of Bakelite, II is a bushing exteriorly screw threaded for insertion and contacting the shell 6, and, III is a short spindle of conductive metal around which are disposed the other members of the sparker and making contact with the point under the head 2 of spindle I in Fig. 1. I and 9 are two sparking points or electrodes between which jumps the discharge.

The explosive gases inside the cylinder must reach its predetermined high compression, and this compression must not be lost or diminished by gas leakage through the threads of the plug. It is at the same time known the troublesome and unavoidable harm and impairing that oil and ashes present in the cylinder of an engine produce in ordinary spark plugs. The spark provided by the sparker of my invention is not so much" influenced by the pressure of the gases and it is a sweep-sliding spark. It requires less sparking voltage to produce a given spark when using the sparker of my invention, and this spark will spread and flatten around the cylindrical surface of the sparker with the increase of gas pressure. The spark obtained will adopt a cylindrical form with the increase of gas pressure and will surround and fill the entire sparking surface of the sparker, every portion of this sparking area being traversed by a portion of the whole spark, thus providing a dense, full and gap filling spark that obviously will sweep and clean the sparking areas of any possible carbon and oil deposits.

The essential elements that compose my compact replaceable spark-gap are, the metallic bushing or shell H, the inner short meta1+ lic spindle ill, the compressed solid dielectric or insulation formed by 8, l2 and I3 between said metallic members, and the downward circular borders I and 9 forming the sparking points. These essential elements can adopt the varied designs and forms already within the experience of a skilled person in the pertaining art, and various other constructions falling within the scope of the appended claims.

I claim:

1. A gapless spark-gap for a spark plug, comprising, a shell, an insulated central spindle sup ported by said shell, the lower tip of said spindle closely adjacent to the lower rim of said shell, the space between said spindle tip and said shell being filled with a solid dielectric material.

2. A gapless sparker for a spark plug having a central insulated metallic spindle and an outer grounded metallic shell, said sparker comprising a composite bushing composed of two ad acent metallic members, a solid dielectric compressed between said metallic members, and means for tightly inserting said sparker in said spark-plug, oneof the metallic members making direct contact with the'grounded shell of said plug, and the other of the two said metallic members making direct contact with the central insulated spindle of said plug.

3. In a spark plug having a central insulated metallic spindle and a grounded shell around said spindle, a gapless sparker for insertion and press-closing the lower entrance of said shell, said sparker comprising two adjacent metallic members, a solid dielectric compressed between said metallic members, said dielectric having a small outside free surface, one of the two mentioned metallic members making direct contact with said insulated metallic spindle thus forming the insulated electrode for said sparker, and the other of the two metallic members being in direct contact with said shell thus forming the grounded electrode for said sparker.

4. In a spark plug, the combination of a grounded shell and a plug-in spark-gap carrying a solid dielectric therein, said spark-gap terminated in adjacent sparking borders.

5. In a spark plug having a grounded metallic shell and an insulated spindle supported by said shell,'a metallic member in electrical contact with said shell, a second metallic member in electrical contact with said metallic spindle, and a solid dielectric compressed between said two metallic members, both of said members terminated in adjacent sparking borders.

6. In a spark plug, a compact spark-gap comprising two adjacent metallic members and a solid dielectric compressed between said two metallic members, both of said members terminated in adjacent sparking borders, these sparking borders separated by a narrow extension of said dielectric presenting a free surface for a spark to jump from border to border over the free surface in said narrow extension.

7. In a spark plug having a grounded shell and an insulated spindle, a compact spark-gap comprising two adjacent metallic members and a solid dielectric compressed between said members, one of said metallic members in contact with said shell and the other member in contact with said spindle, both of said members terminated in adjacent sparking borders.

8. A structure as specified in claim 5 in which the adjacent sparking borders are separated by a narrow extension of the dielectric presenting a free surface for a spark to jump from border to border over the free surface in said narrow extension.

9. A plug-in spark gap for a spark plug, comprising a fast bushing and means for tightly attaching said spark gap as an entire whole in electric-circuit with said spark plug.

10. A plug-in spark gap for a spark plug, composed of two adjacent metallic members and a solid dielectric compressed between and insulating said two metallic members from each other, said two metallic members and said dielectric altogether forming a fast independent whole.

11. A plug-in spark gap for a spark plug, comprising a fast bushing composed of two adjacent metallic members and a solid dielectric inherently compressed between said two metallic members.

12. A plug-in spark gap for a spark plug, comprising a bushing composed of two adjacent metallic members, a solid dielectric compressed between said two members, either member being fast with respect to the other, and means for attaching said spark gap in said spark plug.

13. In combination, two adjacent metallic members and a solid dielectric compressed between said two metallic members, said two metallic members and said dielectric inherently forming a fast whole allowing it to be used as a transferable plug-in spark gap for a spark plug.

14. In a spark plug having a grounded shell and an insulated spindle, a plug-in spark gap for said spark plug, comprising two adjacent metallic members and a solid dielectric compressed between said members, oile of said metallic members in contact with said shell and the other member in contact withi said spindle,

either member being fast with respect to the prising two metallic members and asolid dielectric compressed between said members, said members terminated in adjacent sparking borders, these sparking borders separated by a narrow extension of said dielectric and presenting a free surface for a spark to jump from border to border over the free surface in said narrow extension.

17. In a spark plug having a grounded shell and an insulated spindle supported by said shell, a metallic member in electrical contact with said shell, a second metallic member in electrical contact with said metallic spindle, and a solid dielectric compressed between said two metallic members, said two members and said dielectric altogether forming a transferable fast whole.

HERIBERTO A. VILA. 

